(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Text Book Of Mechanical Engineering"

796

Appendix II.

•i% of nickel increases the cost of the steel by one-third, the
difficulties of introducing it commercially will be understood, so
that though the percentage Ni might rise -to 20 or 30 with
advantage, the practical limit is 3 or 3^, with which there is usually
'3 to '4% carbon. The following list, from actual specimens, will
shew that hardness is due to the presence of carbon :

Percentage Nickel. 2-05 2*62
 3*2 3*4
	Percentage Carbon.
 "22
 •19 •96
 *54 •16
	
	Quality.
 soft soft very hard medium hard soft slightly hard medium hard

		|    -      %&         "'"•
	
		^Vh>%*
	
		^     \\
	
		jfc*             %\
	
		M                   %•
	
		1                  \^
	
All these specimens welded well, and could be bent cold.    As
regards strength and ductility the following are from actual tests :

Use, &c.
	Percentage Nickel.
	Breaking stress tons sq. in.
	Elastic limit tons sq. in.
	Elongation per cent.

Boilerplates   ...... Ship plates  .........
	3
 'Z
	35*7
 ^7
	22*3 26'7
	25 2O

No. 13 Ni Steel .... Gun tube .......
	2'°5
	37-8
 4. 1 '6
	26
	31*5 21 '2

Gun jacket .........
	_
	44*6
	26-8
	2O M

No. 14 Ni Steel   |
 (for propeller shafts) J Gun hoops .......
	3*35
	45
 4.8 7
	33*5
 1O* A
	27'5 2O'C

Wire ............... \
	
	*H*J /
	Ou 4
	zo 5

(easily drawn)    J
	30
	88'7
	
	6*25

In other cases it has reached 40 tons breaking stress with 28
ftons elastic limit, and an elongation equal to mild steel. Compare
this with Forth Bridge steel at 30 tons breaking and 17 tons
•elastic, or the Eiffel Tower steel with 22 tons breaking and r6 tons
elastic. In all cases the nickel steel has the same ductility as
mild steel, but with 30% greater tenacity and 75% greater elastic